1. Field of the Invention
This invention relates to an electronic seal and, in particular, to an electronic seal that detects whether an intruder has gained access to or tampered with the structure being protected. In a preferred embodiment, the electronic seal is used in connection with a coin box of a coin operated pay or public telephone.
The electronic seal is a reusable seal. In a preferred embodiment, the electronic seal has the ability to establish communications with a separate device or location. Also, the electronic seal lends itself to automation of the coin counting function.
2. Description of the Prior Art
Heretofore, the coin boxes of public or pay telephones have been sealed with either plastic seals or a fiber optic seal. At present, the least expensive option, plastic seals, cost from about $0.04 to about $0.10 per seal. Public telephones in the New York Telephone Company region presently use about 9000 seals per day. Obviously, this is very expensive.
There are three specific types of coin box seals available for public telephones. The first is a basic plastic seal. The second is a special heat sensitive plastic seal, while the third is an optical fiber seal.
The basic plastic seal is inserted into and closes around the latch of the coin box. It can only be removed by breaking, e.g. destroying, the seal. The heat sensitive plastic seal is inserted into the coin box latch. The box and seal are then placed into a device that deforms the seal so that it can not be removed without breaking the seal. Lastly, the fiber optic seal is also inserted into the coin box latch. This seal has an optic fiber that will not transmit light from end to end if the seal has been disturbed.
A significant problem with all three seals is that they must be discarded each time the coin box is opened. Specifically, these seals are throw away or nonreusable type seals. Thus, these seals require replacement when the coin box is opened even by authorized personnel. The requirement of continual replacement of these seals is, especially for the great many coin operated pay telephones, very costly. In addition, these three seals do not provide any additional information as to when the opening took place.
Known prior art patents provide complicated systems for tabulating and storing information concerning coins collected from coin operated pay telephones. For example, U.S. Pat. No. 4,123,623 titled Pay Telephone Alarm and Audit, which issued on Oct. 31, 1978 to S. I. McElliott, is directed to an alarm and audit system for compiling such information.
U.S. Pat. No. 4,124,775 titled Coin Box Removal Information Processing Arrangement, which issued on Nov. 7, 1978 to A. Zarouni, is directed to an arrangement for automatically processing a coin box removal signal from a coin telephone station to a central office so that a determination can be made of the exact number and types of coins in the coin box at the time the coin box is removed from the telephone.
Lastly, U.S. Pat. No. 4,928,299 titled Coin Operated Telephone Operation Monitoring Switch Mounting Arrangement, which issued on May 22, 1990 to J. L. Tansky, et al., is directed to an event monitoring system for pay telephones. The system has sensors that are attached to brackets. The sensors generate signals that indicate the removal of a front cover, a vault door and a coin box. A monitoring circuit for the sensors sends an indication to a central telephone office.
These patents provide complicated systems that do not deal with a seal that detects whether the coin box of a public telephone has been opened. They also fail to provide the reusable electronic seal of the present invention that can be removably or permanently placed in the lid of the coin box or be an integral part of the coin box lid.
Significantly, the present electronic seal is reusable, thus eliminating the costs associated with the above noted plastic and fiber optic seals, and is adapted to be removably secured to the coin box. Also, the present electronic seal can be designed for integration into an automated system that eliminates the labor costs of removing the old seals and installing the new seals.